Bring-owls-to-athens meaning

A calque of the Ancient Greek proverb γλαῦκ’ εἰς Ἀθήνας (glauk’ eis Athēnās). The owl, which roosted in the rafters of the old Parthenon (the one burnt by Xerxes I), was the symbol of the city of Athens, and was sacred to its patron goddess, Athena. It was featured on Athens’ silver coins, and as Athens both mined its own silver and minted its own coins, bringing owls (either the real birds, or the coins) to Athens would be pointless.